losing the arch in the lower back at the bottom of the squat

[redivote]

hey coach rippetoe
here is my squat:
http://www.youtube.com/watch?v=51srxHBSldQ
as u can see, i lose my arch in the lower back...
how can i fix this???
and tell me plz, how critical is it to keep this arch?? i guss that if i get round during a big 5-6rm squats its pretty dangerous??
tnx

[Mark Rippetoe]

u shud luk hear at my anser to thez guise, wut i has already rote:

http://strengthmill.net/forum/showthread.php?t=177

Now, please try to improve your typing.

[redivote]

thanks, and sorry

[Mark Rippetoe]

That should read: "Thanks, and sorry." We writers are all about case and punctuation.